Solar battery module and solar battery array

ABSTRACT

A solar battery module ( 40 ) is constituted by a stack of: a plurality of solar battery strings ( 30 ) and bus sections ( 32 ) connected to both ends of each of the plurality of solar battery strings ( 30 ); flexible resin layers ( 33   a  through  33   c ); and a flexible resin film ( 34 ). The flexible resin layers ( 33   a  through  33   c ) and the flexible resin film ( 34 ) have, on a light receiving surface side of solar battery cells ( 20 ), holes through which the bus sections ( 32 ) are each partially exposed. The exposed parts of the bus sections ( 32 ) serve as a respective plurality of electrically-connecting means ( 32   a ). A solar battery array ( 41 ) is constituted by a plurality of solar battery modules ( 40 ). The plurality of solar battery modules ( 40 ) are electrically connected with each other via the plurality of electrically-connecting means ( 32   a ). This makes it possible to achieve a large-scale solar battery array ( 41 ) with high mechanical strength.

TECHNICAL FIELD

The present invention relates to a solar battery module and a method forproducing a solar battery module.

BACKGROUND ART

In recent years, a solar battery module has been attracting attention inview of effective use of resources and prevention of environmentalcontamination etc., because the solar battery module directly convertssunlight into electrical energy. In particular, since there has beenincreasing need for a lightweight and large-area solar battery module,development of such a solar battery module has been carried out.

For example, Patent Literature 1 discloses a solar battery modulemounted on a sheet member. The solar battery module shown in PatentLiterature 1 is described below with reference to FIGS. 12 and 13. FIG.12 is a plan view illustrating (i) a sheet member 61 and (ii) a solarbattery module 60 mounted on the sheet member 61. FIG. 13 is across-sectional view illustrating the solar battery module 60.

As illustrated in FIG. 12, the solar battery module 60 is sewed on thesheet member 61 with a thread 62. Further, as illustrated in FIG. 13,the solar battery module 60 is configured such that solar battery cells65 are sealed within a sealing resin 66, which is sandwiched between alight receiving surface protection film 63 and a back surface protectionfilm 64.

According to Patent Literature 1, a large-area solar battery module isformed by sewing a plurality of the foregoing solar battery modules 60onto the sheet member 61. Note however that, while volume of the lightreceiving surface protection films 63 and the back surface protectionfilms 64 with respect to volume of the large-area solar battery moduleis approximately 66%, volume of the sheet member 61 with respect to thevolume of the large-area solar battery module is approximately 33%.Further, the sheet member 61 is greater in weight than the lightreceiving surface protection films 63 etc., because the sheet member ismade from material with high mechanical strength. Accordingly, totalweight of the large-area solar battery module is markedly large becauseof the sheet member 61.

On the other hand, there has been developed a large-area solar batterysheet that is constituted by a combination of flexible solar batterymodules without a sheet member.

For example, a conventional solar battery sheet array illustrated inFIG. 15 is described below. (a) of FIG. 15 is a plan view illustratingthe solar battery sheet array. (b) of FIG. 15 is a cross-sectional viewtaken along line I-I′ of (a) of FIG. 15.

The solar battery sheet array illustrated in FIG. 15 is constituted by aplurality of unit solar battery sheets 110. FIG. 14 illustrates one ofthe plurality of unit solar battery sheets 110. (a) of FIG. 14 is a planview illustrating one of the unit solar battery sheet. (b) of FIG. 14 isa cross-sectional view taken along line H-H′ of (a) of FIG. 14. The unitsolar battery sheet 110 is configured such that (i) solar battery cells104 are electrically connected in series with one another via interconnectors 105, and (ii) both ends of an electrical connection among thesolar battery cells 104 are connected to respective bus sections 106 a,which collect electric power.

Each of the bus sections 106 a of the unit solar battery sheet 110 isprotruded from a flexible resin film 101, a back surface protectionmember 102, and a silicon resin 103 so that the plurality of unit solarbattery sheets 110 can be electrically connected with one another asillustrated in FIG. 15.

The solar battery sheet array shown in FIG. 15 is configured such thatprotruded parts of bus sections 106 of adjacent ones of the plurality ofunit solar battery sheets 110 are welded together to form a welded part107 and thereby the plurality of unit solar battery sheets 110 areelectrically connected with one another via the welded parts 107. Inaddition, adjacent ones of the plurality of unit solar battery sheets110 are physically connected with each other with use of an adhesiveagent 108. The adhesive agent 108 fixes also a corresponding one of thewelded parts 107, and has protection films 109 on its both surfaces.

According to the configuration as shown in FIG. 15, a large-area solarbattery sheet array is formed without a sheet member. Therefore, withthis configuration, it is possible to achieve a lightweight andlarge-area solar battery sheet array.

Citation List Patent Literatures

Patent Literature 1

Japanese Patent Application Publication, Tokukai, 2006-339684 A(Publication Date: Dec. 14, 2006)

SUMMARY OF INVENTION Technical Problem

However, according to the solar battery sheet array shown in FIG. 15, aconnection part between adjacent ones of the plurality of solar batterymodules 110 is not uniform in its flexibility and strength. For example,see a cross-sectional view taken along line J-J′. According to thecross-sectional view, a left one-third of the connection part betweenadjacent ones of the plurality of solar battery modules 110 isconstituted by the protection films 109, the adhesive agent 108, andcorresponding ones of the bus sections 106. On the other hand, the othertwo-thirds of the connection part is constituted by the protection films109 and the adhesive agent 108. That is, the connection part shown inthe cross-sectional view taken along line J-J′ is not uniform in itsstructure.

For example, in a case where the protection films 109 are made from aradiation-resistant film having high flexibility and low strength, thetwo-thirds of the connection part shown in the cross-sectional viewtaken along line J-J′ is constituted by (i) the protection films 109with low strength and (ii) the adhesive agent 108. That is, thetwo-thirds of the connection part has markedly low strength.

On the other hand, for example in a case where the protection films 109are made from a radiation-resistant film having low flexibility and highstrength, the left one-third of the connection part shown in thecross-sectional view taken along line J-J′ includes (i) the protectionfilms 109 with low flexibility and (ii) the bus sections 106 made frommetal. That is, the left one-third of the connection part has markedlylow flexibility.

As such, according to the solar battery sheet array shown in FIG. 15, itis difficult to achieve both of flexibility and mechanical strength ofthe connection part between adjacent ones of the plurality of solarbattery modules.

The present invention has been made in view of the problems, and anobject of the present invention is to provide (i) a large-scale solarbattery array with improved flexibility and improved mechanical strengthand (ii) a solar battery module for constituting the solar batteryarray.

Solution to Problem

In order to attain the above object, a solar battery module inaccordance with the present invention is a solar battery module forconstituting a solar battery array, including: at least one solarbattery string that is constituted by a plurality of solar battery cellselectrically connected in series with each other; bus sectionselectrically connected with respective endmost ones of the plurality ofsolar battery cells that constitute said at least one solar batterystring; and at least one flexible resin layer provided on each of bothsides, which are a first side and a second side, of the solar batterymodule so as to sandwich said at least one solar battery string and thebus sections, the first side of the both sides of the solar batterymodule having first holes, through which the bus sections are eachpartially exposed, and the bus sections having areas which are exposedthrough the respective first holes, the areas serving as a respectiveplurality of electrically-connecting means.

A plurality of solar battery modules in accordance with the presentinvention are to constitute a solar battery array by being electricallyconnected with each other. In a case where each of the plurality of thesolar battery modules is constituted by a flexible material, the each ofthe plurality of the solar battery modules is used as a flexible solarbattery sheet. Accordingly, the solar battery array constituted by theplurality of solar battery modules is used as a flexible solar batterysheet array.

The plurality of solar battery modules in accordance with the presentinvention are electrically connected with each other via the pluralityof electrically-connecting means of the bus sections. Note here that theplurality of electrically-connecting means of the bus sections can beconnected with a wire by soldering etc. According to this configuration,the plurality of solar battery modules can be connected with each othervia the wire. The bus sections are connected with respective endmostones of the plurality of solar battery cells connected with each other,and collect electric power. Generally, the bus sections are made frommetal.

According to this configuration, the plurality ofelectrically-connecting means of the bus sections are exposed throughthe respective first holes. Therefore, each of the bus sections isconfigured such that it does not protrude from the at least one flexibleresin layer. Accordingly, there are no other members (e.g., the bussections) between adjacent ones of the plurality of solar batterymodules when the plurality of solar battery modules are electricallyconnected with each other. This makes it possible to achieve anadvantage that the connected plurality of solar battery modules as awhole maintains its flexibility and keeps its mechanical strengthuniform.

A solar battery array in accordance with the present invention includes:a plurality of the foregoing solar battery modules, the plurality ofsolar battery modules being electrically connected in series with eachother via corresponding ones of the plurality of electrically-connectingmeans, each of which serves as an end of an electrical connection in acorresponding one of the solar battery strings electrically connected inseries with each other.

According to this configuration, it is possible to easily produce alarge-scale solar battery array in accordance with the present inventionby connecting the plurality of solar battery modules. In addition,according to the solar battery array in accordance with the presentinvention, it is possible to improve flexibility of the entire solarbattery array because there are no members such as the bus sectionsbetween adjacent ones of the plurality of solar battery modules.

Advantageous Effects of Invention

A solar battery module in accordance with the present invention includesa plurality of electrically-connecting means on one of both sides of thesolar battery module. Accordingly, by combining a plurality of suchsolar battery modules, it is possible to make a large-scale solarbattery array having improved flexibility and improved mechanicalstrength.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a solar battery array of a first embodiment inaccordance with the present invention. (a) of FIG. 1 is a plan view. (b)of FIG. 1 is a cross-sectional view taken along line D-D′ of (a) ofFIG. 1. (c) of FIG. 1 is a cross-sectional view taken along line E-E′ of(a) of FIG. 1.

FIG. 2 is a plan view illustrating a light receiving surface of one ofsolar battery cells.

FIG. 3 is a cross-section view, illustrating the solar battery cell,which is taken along line A-A′ of FIG. 2.

FIG. 4 illustrates one of solar battery strings.

FIG. 5 illustrates how the solar battery strings are arranged.

FIG. 6 illustrates a temporarily-jointed solar battery module. (a) ofFIG. 6 is a plan view. (b) of FIG. 6 is a cross-sectional view takenalong line B-B′ of (a) of FIG. 6.

FIG. 7 is a view with reference to which a production process for asolar battery module of the first embodiment in accordance with thepresent invention is described.

FIG. 8 illustrates the solar battery module of the first embodiment inaccordance with the present invention. (a) of FIG. 8 is a plan view. (b)of FIG. 8 is a cross-sectional view taken along line C-C′ of (a) of FIG.8.

FIG. 9 illustrates how solar battery strings are arranged.

FIG. 10 illustrates a solar battery module of a second embodiment inaccordance with the present invention. (a) of FIG. 10 is a plan view.(b) of FIG. 10 is a cross-sectional view taken along line F-F′ of (a) ofFIG. 10.

FIG. 11 illustrates a solar battery array of the second embodiment inaccordance with the present invention. (a) of FIG. 11 is a plan view.(b) of FIG. 11 is a cross-sectional view taken along line G-G′ of (a) ofFIG. 11.

FIG. 12 is a plan view illustrating a conventional solar battery module.

FIG. 13 is a cross-sectional view illustrating a conventional solarbattery module.

FIG. 14 illustrates a conventional solar battery module. (a) of FIG. 14is a plan view. (b) of FIG. 14 is a cross-sectional view.

FIG. 15 illustrates a conventional solar battery array. (a) of FIG. 15is a plan view. (b) of FIG. 15 is a cross-sectional view taken alongline I-I′ of (a) of FIG. 15. (c) of FIG. 15 is a cross-sectional viewtaken along line J-J′ of (a) of FIG. 15.

DESCRIPTION OF EMBODIMENTS Embodiment 1

A first embodiment in accordance with the present invention is describedbelow with reference to FIGS. 1 through 8.

(Solar Battery Cells 20)

First, the following description discusses, with reference to FIGS. 2and 3, how solar battery cells 20 used in the present embodiment areschematically configured. FIG. 2 is a plan view illustrating a lightreceiving surface of one of the solar battery cells 20. FIG. 3 is across-sectional view, illustrating the solar battery cell 20, which istaken along line A-A′ of FIG. 2.

Each of the solar battery cells 20 has (i) a light receiving surface forreceiving sunlight and (ii) a non-light receiving surface opposed to thelight receiving surface. Note that, in this Specification, a side onwhich the light receiving surface of each of the solar battery cells 20is situated is hereinafter referred to as a light receiving surfaceside, whereas the other side on which the non-light receiving surface ofthe each of the solar battery cells 20 is situated is hereinafterreferred to as a non-light receiving surface side.

As illustrated in FIGS. 2 and 3, each of the solar battery cells 20 isconstituted by a multilayered semiconductor layer 22, an n-typeelectrode 25, p-type electrodes 26, and a back surface electrode 27. Themultilayered semiconductor layer 22 is constituted by: a solar batterylayer 23 including a p-n junction between a p-type region and an n-typeregion; a contact layer 24 via which the p-type electrodes 26 and thesolar battery layer 23 are electrically connected with each other; and acontact layer 29 via which the n-type electrode 25 and the solar batterylayer 23 are electrically connected with each other.

The n-type electrode 25 has a comb-teeth shape, and is provided on asurface, of the contact layer 29, which is on the light receivingsurface side. Each of the p-type electrodes 26 has a rectangular shape,and is provided on a surface, of the contact layer 24, which is on thelight receiving surface side. The back surface electrode 27 covers anentire surface of each of the solar battery cells 20, and is provided ona surface, of the contact layer 24, which is on the non-light receivingsurface side.

In the present embodiment, each of the solar battery cells 20 isprovided with (i) the n-type electrode 25 having three pads and (ii)three p-type electrodes 26. Note, however, that the present invention isnot limited to this configuration. Further, shape of each of the backsurface electrode 27, the n-type electrode 25, and the p-type electrodes26 is not limited to those described above, as long as they function asconstituents of each of the solar battery cells 20. Furthermore, theconfigurations of the n-type electrode 25 and the p-type electrodes 26are interchangeable.

Each of the solar battery cells 20 has, on its light receiving surfaceside, inter connectors 31 provided on the n-type electrode 25 and on thep-type electrodes 26. The each of the solar battery cells 20 can furtherhave an antireflective film on its light receiving surface.

(Production Method for Solar Battery Cells 20)

The following description discusses a production method for the solarbattery cells 20 with reference to FIGS. 2 and 3.

The production method for the solar battery cells 20 includes: a step offorming epitaxial layers on a semiconductor substrate; a step of forminga back surface electrode 27 on the non-light receiving surface side; astep of removing the semiconductor substrate; a step of forming n-typeelectrodes 25 and p-type electrodes 26 on the light receiving surfaceside; and a step of separating out the solar battery cells 20.

Each of the steps included in the production method for the solarbattery cells 20 is specifically described below. Note, however, that aproduction method of the present invention is not limited to theproduction method as described below.

(1) Step of Forming Epitaxial Layers on Semiconductor Substrate

The semiconductor substrate used in this step is for example: anelemental semiconductor substrate such as that made from silicon (Si)and/or germanium (Ge); or a compound semiconductor substrate such asthat made from gallium arsenic (GaAs). The semiconductor substrate ispreferably a single crystal semiconductor substrate.

First, layers are epitaxially-grown on the semiconductor substrate so asto obtain a multilayered semiconductor layer 22, which is constitutedby: a contact layer 24; a contact layer 29; and a solar battery layer 23including p-n junctions. The multilayered semiconductor layer 22 thusobtained preferably consists of epitaxial layers with small deformation.A thickness of the multilayered semiconductor layer 22 (i.e., athickness of each of the resulting solar battery cells) is preferablynot less than 0.5 μm; however, the thickness is preferably not more than30 μm so as to ensure flexibility of the solar battery cells 20. Themultilayered semiconductor layer 22 can be a compound semiconductorlayer, which is a multilayer film including the p-n junctions.

As an alternative, the multilayered semiconductor layer 22 can be formedby MBE (molecular beam epitaxy), MOCVD (metalorganic chemical vapordeposition), VPE (vapor phase epitaxy), or the like.

(2) Step of Forming Back Surface Electrode 27 on Non-Light ReceivingSurface Side

A back surface electrode 27 is formed on a surface of the multilayeredsemiconductor layer 22 by a generally-used electrode forming method suchas a vapor-deposition method. In order for the back surface electrode 27to serve as a support of the multilayered semiconductor layer 22, athickness of the back surface electrode 27 is preferably not less than 1μm. On the other hand, in order to prevent each of the solar batterycells 20 from warping due to a difference between thermal linearcoefficients of expansion between the multilayered semiconductor layer22 and the back surface electrode 27, the thickness of the back surfaceelectrode 27 is preferably not more than 8 μm. The back surfaceelectrode 27 can be made from a conductive material such as silver (Ag).

(3) Step of Removing Semiconductor Substrate

The entire semiconductor substrate, or the entire semiconductorsubstrate and part of the multilayered semiconductor layer 22, is/areremoved by a generally-used etching method so as to cause the contactlayer 29 to be exposed. As an alternative, the semiconductor substratecan be removed from the multilayered substrate layer 22 by an epitaxiallift-off method etc.

This step includes formation of mesas, on which n-type electrodes 25 andp-type electrodes 26 are to be formed. First, masks are formed by agenerally-used photolithographic method so as to cover only necessaryparts of the solar battery layer 23. Then, unnecessary parts of thesolar battery layer 23 are removed by an etching method so that thecontact layer 24 is partially exposed.

The etching method can be a dry etching method or a wet etching method.Note, however, that it is preferable to employ a selective etchingmethod, in which the etching process substantially stops upon reaching asurface of a certain layer.

(4) Step of Forming N-type Electrodes 25 and P-type Electrodes 26

The n-type electrodes 25 and the p-type electrodes 26 are formed on asurface, of the solar battery layer 23, which is on the light receivingsurface side. The n-type electrodes 25 and the p-type electrodes 26 areformed by a generally-used electrode forming method such as aphotolithographic method, a vapor-deposition method, a lift-off method,or a sintering method. The n-type electrodes 25 and the p-typeelectrodes 26 can be made from a conductive material such as silver(Ag). Either the n-type electrodes 25 or the p-type electrodes 26 can beformed first, or the n-type electrodes 25 and the p-type electrodes 26can be formed concurrently.

(5) Step of Separating Solar Battery Cells 20

From the board thus obtained through the above steps, necessary partsonly are separated out as the solar battery cells 20. The solar batterycells 20 can be separated out by (i) making a cut in a peripheraloutline of each of the solar battery cells 20 by a dicing method or ascribing method, and then (ii) separating out the solar battery cells 20by an expanding method or a breaking method.

The solar battery cells 20 are obtained through the above steps. Next, astep of forming the inter connectors 31 on the obtained solar batterycells 20 is described below.

(6) Step of Connecting Inter Connectors

The inter connectors 31 are connected to the re-type electrodes 25 andthe p-type electrodes 26 by a spot welding method. The inter connectors31 can be made from a conductive material such as silver (Ag). Shape ofeach of the inter connectors 31 can be any shape, as long as the each ofthe inter connectors 31 can be drawn out of the peripheral outline ofeach of the solar battery cells 20.

(Solar Battery Module 40)

The following description discusses a solar battery module 40 of thepresent embodiment with reference to FIG. 8. FIG. 8 illustrates thesolar battery module 40. (a) of FIG. 8 is a plan view. (b) of FIG. 8 isa cross-sectional view taken along line C-C′ of (a) of FIG. 8.

The solar battery module 40 is constituted by: the solar battery cells20; the inter connectors 31; bus sections 32; flexible resin layers 33a, 33 b, and 33 c; and a flexible resin film 34.

As illustrated in (a) of FIG. 8, the solar battery module 40 includes:five solar battery cells 20 electrically connected in series with oneanother via corresponding ones of the inter connectors 31 to form astring. Such a string constituted by a plurality of solar battery cells20 electrically connected in series with one another is referred to as asolar battery string 30.

Each end of the solar battery string 30 is connected with acorresponding one of the bus sections 32 via corresponding ones of theinter connectors 31. The bus sections 32 are provided at both ends ofthe solar battery string 30, and collect electric power. The solarbattery module 40 includes three solar battery strings 30, each of whichis provided with the bus sections 32.

Note here that, in the present invention, (i) the number of the solarbattery cells 20 included in each of the solar battery strings 30 and(ii) the number of the solar battery strings 30 are not limited to thosedescribed above, and can be any numbers.

As illustrated in (b) of FIG. 8, the solar battery strings 30 include astack of (i) the flexible resin layers 33 a, 33 b, and 33 c, and (ii)the flexible resin film 34. The flexible resin layer 33 c is provided onthe light receiving surface side of the solar battery strings 30. Theflexible resin layer 33 a, the flexible resin film 34, and the flexibleresin layer 33 b are provided, on the non-light receiving surface sideof the solar battery strings 30, such that they are on top of oneanother in this order from the solar battery cells 20 toward thenon-light receiving surface side.

The flexible resin layer 33 a, the flexible resin layer 33 b, and theflexible resin film 34, which are provided on the non-light receivingsurface side, have holes (first holes) 38 penetrating them. Through theholes 38, the bus sections 32 are each partially exposed. The exposedplurality of electrically-connecting means 32 a. The plurality ofelectrically-connecting means 32 a are on the non-light receivingsurface side. Note here that, although one hole 38 is formed in each ofthe bus sections 32 in the present embodiment, two or more holes 38 canbe formed in each of the bus sections 32 as long as mechanical strengthcan be kept.

According to this configuration, a plurality of solar battery modules 40can be connected with each other via the plurality ofelectrically-connecting means 32 a so as to form a solar battery array.Since such a solar battery array is configured such that adjacent onesof the plurality of solar battery modules 40 are connected with eachother without any member therebetween, the connection part between theadjacent ones of the plurality of battery modules 40 has improvedflexibility.

(Production Method for Solar Battery Module 40)

The following description discusses a production method for the solarbattery module 40 with reference to FIGS. 4 through 8. FIGS. 4 through 7are views with reference to which to explain steps included in theproduction method for the solar battery module 40.

First, five solar battery cells 20 are prepared. Then, inter connectors31 are welded to the solar battery cells 20 by a spot welding method,via which inter connectors the solar battery cells 20 are electricallyconnected in series with one another (see FIG. 4). In this way, a solarbattery string 30 is formed.

Next, other inter connectors 31 are welded to both ends of the solarbattery string 30 also by the spot welding method. The both ends of thesolar battery string 30 are connected with the bus sections 32 via suchinter connectors 31. The bus sections 32 can be made from metal.

Then, as illustrated in FIG. 5, three solar battery strings 30 eachhaving the bus sections 32 connected at its both ends are arranged inparallel with one another. According to FIG. 5, the rightmost one andthe leftmost one of the solar battery strings 30 are arranged such thattheir n-type regions are on an upper side of FIG. 5 and their p-typeregions are on a lower side of FIG. 5. The midmost one of the solarbattery strings 30 is arranged such that its n-type region is on thelower side of FIG. 5 and its p-type region is on the upper side of FIG.5. Note here that, the solar battery strings 30 can be arranged suchthat adjacent ones of the solar battery strings 30 have their n-typeregions and p-type regions on opposite sides (e.g., FIG. 5), or can bearranged such that all the solar battery strings 30 have their n-typeregions and p-type regions on the same sides.

Then, the flexible resin layer 33 a is applied to the flexible resinfilm 34, which has openings formed in areas corresponding to positionsof the bus sections 32. Thereafter, such a flexible resin film 34 islaminated to the solar battery strings 30 that are arranged in parallelwith one another (see FIG. 6). Note here that the flexible resin film 34is laminated such that its openings are on the non-light receivingsurface side of the solar battery cells 20. In this way, atemporarily-jointed solar battery module 36 is obtained.

The flexible resin film 34 is preferably a polyimide film or a fluorineresin film. It is further preferable that front and back surfaces of thepolyimide film or of the fluorine resin be subjected to a coronadischarge treatment or be treated with a chemical agent etc. so that thefront and back surfaces become easy to adhere. One specific example ofsuch a film is KAPTON 100EN (manufactured by DU PONT-TORAY CO., LTD.) orthe like, whose front and back surfaces have been subjected to thecorona discharge treatment so that the surfaces become easy to adhere.

The flexible resin layers 33 a, 33 b, and 33 c are preferably made fromtransparent flexible resin with high adhesiveness. Examples of suchflexible resin encompass: epoxy resin, urethane resin, silicon resin,acrylic resin, and fluorine resin. Specific example of such flexibleresin is DC93-500 (manufactured by Dow Corning Toray Co., Ltd).

Then, as illustrated in FIG. 7, the flexible resin layers 33 b and 33 care applied to respective two exfoliate resin films 37. Such twoexfoliate resin films 37 are laminated to the light receiving surfaceside and the non-light receiving surface side of the temporally-joinedsolar battery module 36, respectively.

The exfoliate films 37 serve as exfoliate paper. Each of the exfoliatefilms 37 is preferably a polyimide film or a fluorine resin film. Aspecific example of each of the exfoliate films 37 is KAPTON 200H(manufactured by DU PONT-TORAY CO., LTD.) or the like.

The laminating is carried out preferably with use of a generally-usedlamination device under a condition where a heater temperature is a roomtemperature and a pressure is 0.02 MPa.

Then, as illustrated in FIG. 8, the two exfoliate films 37 are removed.Thereafter, parts of the flexible resin layers 33 a and 33 b, whichparts correspond to positions of the openings in the flexible resin film34, are removed. In this way, each of the bus sections 32 is partiallyexposed to outside.

The flexible solar battery module 40 is obtained through the abovesteps.

(Solar Battery Array 41)

A solar battery array 41 can be constituted by a plurality of theforegoing flexible solar battery modules 40. The following descriptiondiscusses the solar battery array 41 with reference to FIG. 1. FIG. 1illustrates the solar battery array 41. (a) of FIG. 1 is a plan view.(b) of FIG. 1 is a cross-sectional view taken along line D-D′ of (a) ofFIG. 1. (c) of FIG. 1 is a cross-sectional view taken along line E-E′ of(a) of FIG. 1.

The solar battery array 41 is constituted by three solar battery modules40 connected with one another.

As illustrated in (a) of FIG. 1, the solar battery strings 30 in each ofthe solar battery modules 40 are connected in series with one anothervia corresponding ones of wires 43, which are connected with the bussections 32. Similarly, the three solar battery modules 40 in the solarbattery array 41 are connected in series with one another viacorresponding ones of the wires 43. In this way, all the solar batterycells 20 included in the solar battery array 41 are electricallyconnected in series with one another. Note here that the wires 43 can beconnected to the bus sections 32 by soldering.

According to this configuration, an electrical connection betweenadjacent ones of the solar battery modules 40 is made on the non-lightreceiving side of the solar battery array 41. Therefore, there are nometal components such as the bus sections 32 between adjacent ones ofthe solar battery modules 40 connected with each other. Accordingly,flexibility of the connection part between the adjacent ones of thesolar battery modules 40 is improved.

Further, as illustrated in (b) of FIG. 1, the solar battery array 41 isconfigured such that adjacent ones of the solar battery modules 40overlap each other at their neighboring ends, with their neighboringends in contact with each other. The overlapped areas of the respectiveadjacent ones of the solar battery modules 40 are physically connectedwith each other with an adhesive agent 42. The adhesive agent is notlimited to a particular kind. A specific example of the adhesive agentis RTV-S691 (manufactured by WACKER ASAHIKASEI SILICONE CO., LTD.) orthe like.

According to this configuration, the solar battery array 41 isconfigured such that the connection part between adjacent ones of thesolar battery modules 40 is uniform in its physical structure.Accordingly, mechanical strength of the connection part is improved.

Embodiment 2

A second embodiment in accordance with the present invention isdescribed below with reference to FIGS. 9 through 11. Note here thatconstituents corresponding to the constituents of Embodiment 1 areassigned identical referential numerals.

(Solar Battery Module 50)

A solar battery module 50 of the present embodiment is described belowwith reference to FIG. 10. FIG. 10 illustrates a solar battery module ofa second embodiment in accordance with the present invention. (a) ofFIG. 10 is a plan view. (b) of FIG. 10 is a cross-sectional view takenalong line F-F′ of (a) of FIG. 10.

The solar battery module 50 is different from the foregoing solarbattery module 40 of Embodiment mainly in terms of (i) the number ofsolar battery cells 20 and the number of solar battery strings 30 a,(ii) a laminated structure of flexible resin layers 45 a and 45 b andflexible resin films 46 a and 46 b, which are laminated to the solarbattery strings 30 a, and (iii) holes (second holes) 48 formed on thelight receiving surface side. In view of this, the following descriptionmainly discusses these differences.

As illustrated in (a) of FIG. 10, the solar battery module 50 includestwo solar battery strings 30 a. Each of the solar battery strings 30 aincludes three solar battery cells 20. Note however that, in the presentinvention, the number of the solar battery cells 20 and the number ofthe solar battery strings 30 a are not limited to those described above,and can be any numbers depending on the situation.

As illustrated in (b) of FIG. 10, the solar battery module 50 isconfigured such that the flexible resin layers 45 a and 45 b and theflexible resin films 46 a and 46 b are laminated to the solar batterystrings 30 a, each of which has its ends connected with respective bussections 32. The flexible resin layer 45 b and the flexible resin film46 b are provided such that they are on top of each other in this orderfrom the solar battery cells 20 toward the light receiving surface side.The flexible resin layer 45 a and the flexible resin film 46 a areprovided such that they are on top of each other in this order from thesolar battery cells 20 toward the non-light receiving side. That is,both sides of the solar battery module 50 are protected by the flexibleresin films 46 a and 46 b, respectively.

The solar battery module 50 has, on its non-light receiving surfaceside, holes 47 penetrating the flexible resin layer 45 a and theflexible resin film 46 a. The holes 47 are formed in areas correspondingto positions of the bus sections 32. Further, the solar battery module50 has, on its light receiving surface side, the holes 48 penetratingthe flexible resin layer 45 b and the flexible resin film 46 b. Theholes 48 are formed in areas corresponding to the positions of the bussections 32. That is, part of each of the bus sections 32 is exposedthrough a corresponding one of the holes 47 and a corresponding one ofthe holes 48 on the non-light receiving surface side and on the lightreceiving side, respectively.

(Production Method for Solar Battery Module 50)

The following description discusses a production method for the solarbattery module 50. The following description mainly discussesdifferences between the production method for the solar battery module50 and that for the solar battery module 40 of Embodiment 1.

First, as illustrated in FIG. 9, two solar battery strings 30 a areprepared. The solar battery strings 30 a are arranged in the same way asin Embodiment 1. FIG. 9 illustrates how the solar battery strings 30 aare arranged.

Next, the flexible resin layers 45 a and 46 b are applied to theflexible resin films 46 a and 46 b, respectively, by a roll coatermethod. Note here that the flexible resin films 46 a and 46 b have, inadvance, openings formed in areas corresponding to positions of the bussections 32.

Then, the flexible resin films 46 a and 46 b, to which the flexibleresin layers 45 a and 45 b are applied, are laminated to the non-lightreceiving surface side and the light receiving surface side of the solarbattery strings 30 a having the bus sections 32 connected thereto,respectively. The laminating is carried out preferably by agenerally-used lamination device for terrestrial application, under acondition where a heater temperature is a room temperature and apressure is 0.01 MPa.

Each of the flexible resin films 46 a and 46 b is preferably a resinfilm with high transparency and high heat resistance, unlike theflexible resin film 34 of Embodiment 1. Examples of such a resin filmencompass a resin film made from: an ethylene tetrafluoride-ethylenecopolymer, vinylidene fluoride resin, polytrifluorochloroethylene resin,acrylic resin, polytrifluorochloroethylene resin-coated acrylic resin,or polyester resin. A specific example of such a resin film is AFLEX50NS (manufactured by ASAHI GLASS Co., LTD.) or the like.

Thereafter, parts of the flexible resin layer 45 a, which partscorrespond to positions of the openings in the flexible resin film 46 a,are removed so that each of the bus sections 32 is partially exposed.Similarly, parts of the flexible resin layer 45 b, which partscorrespond to positions of the openings in the flexible resin film 46 b,are removed so that each of the bus sections 32 is partially exposed.

The solar battery module 50 is obtained through the above steps.

(Solar Battery Array 51)

A solar battery array 51 is constituted by a plurality of the foregoingsolar battery modules 40, and includes solar battery cells 20 which areelectrically connected in series with one another. The followingdescription discusses the solar battery array 51 with reference to FIG.11. FIG. 11 illustrates the solar battery array 51. (a) of FIG. 11 is aplan view. (b) of FIG. 11 is a cross-sectional view taken along lineG-G′ of (a) of FIG. 11.

The solar battery array 51 of the present embodiment is different fromthe foregoing solar battery array 41 of Embodiment 1 mainly in thatsolar battery modules 50 are physically connected with one another withuse of rivets.

Since flexible resin films 46 a and 46 b each having high strength areprovided as outermost layers of each of the solar battery modules 50,the rivets are suitable for physical connection between adjacent ones ofthe solar battery modules 50 that constitute the solar battery array 51.Note, however, that the adjacent ones of the solar battery modules 50are physically connected with each other not necessarily with use of therivets, and therefore can be physically connected with each other bysewing.

Further, since the solar battery array 51 has holes 47 and holes 48 onits non-light receiving surface side and light receiving surface side,respectively, wires 53 can be welded to bus sections 32 by a spotwelding method. The spot welding method is such that (i) electrodes arepressed to a surface of each of the bus sections 32 through acorresponding one of the holes 47, which surface is right opposite to acorresponding one of a plurality of electrically-connecting means 32 a,and then (ii) an electrical current is applied between the electrodes.In this way, the wires 53 are welded to the plurality ofelectrically-connecting means 32 a.

It should be noted that the number of solar battery cells in each of thesolar battery strings, the number of the solar battery strings in eachof solar battery modules, and the number of the solar battery modules inthe solar battery array are not limited to those described above, andcan be any numbers depending on the situation. Further, positions of thesolar battery modules constituting the solar battery array are notlimited to those described above, and can be any positions depending onthe situation.

As described so far, in order to attain the above object, a solarbattery module in accordance with the present invention is a solarbattery module for constituting a solar battery array, including: atleast one solar battery string that is constituted by a plurality ofsolar battery cells electrically connected in series with each other;bus sections electrically connected with respective endmost ones of theplurality of solar battery cells that constitute said at least one solarbattery string; and at least one flexible resin layer provided on eachof both sides, which are a first side and a second side, of the solarbattery module so as to sandwich said at least one solar battery stringand the bus sections, the first side of the both sides of the solarbattery module having first holes, through which the bus sections areeach partially exposed, and the bus sections having areas which areexposed through the respective first holes, the areas serving as arespective plurality of electrically-connecting means.

A plurality of solar battery modules in accordance with the presentinvention are to constitute a solar battery array by being electricallyconnected with each other. In a case where each of the plurality of thesolar battery modules is constituted by a flexible material, the each ofthe plurality of the solar battery modules is used as a flexible solarbattery sheet. Accordingly, the solar battery array constituted by theplurality of solar battery modules is used as a flexible solar batterysheet array.

The plurality of solar battery modules in accordance with the presentinvention are electrically connected with each other via the pluralityof electrically-connecting means of the bus sections. Note here that theplurality of electrically-connecting means of the bus sections can beconnected with a wire by soldering etc. According to this configuration,the plurality of solar battery modules can be connected with each othervia the wire. The bus sections are connected with respective endmostones of the plurality of solar battery cells connected with each other,and collect electric power. Generally, the bus sections are made frommetal.

According to this configuration, the plurality ofelectrically-connecting means of the bus sections are exposed throughthe respective first holes. Therefore, each of the bus sections isconfigured such that it does not protrude from the at least one flexibleresin layer. Accordingly, there are no other members (e.g., the bussections) between adjacent ones of the plurality of solar batterymodules when the plurality of solar battery modules are electricallyconnected with each other. This makes it possible to achieve anadvantage that the connected plurality of solar battery modules as awhole maintains its flexibility and keeps its mechanical strengthuniform.

The solar battery module in accordance with the present invention ispreferably configured such that: a number of said at least one solarbattery string is two or more; and the two or more solar battery stringsare electrically connected in series with each other via correspondingones of the plurality of electrically-connecting means.

According to this configuration, the two or more solar battery stringsin the solar battery module are connected with each other via theplurality of electrically-connecting means of the respective bussections, which are at both ends of the two or more solar batterystrings. Accordingly, it is possible to downsize each of the bussections of the solar battery module in accordance with the presentinvention, as compared with a conventional configuration in which eachof some of the bus sections belongs to two or more solar batterystrings. This makes it possible to improve flexibility of the solarbattery module.

Further, the two or more solar battery strings in the solar batterymodule can be connected with each other via the wire, which is connectedwith corresponding ones of the plurality of electrically-connectingmeans of the bus sections. In this way, the two or more battery stringsare electrically connected in series with each other easily.

The solar battery module in accordance with the present invention ispreferably configured such that: light receiving surfaces of therespective plurality of solar battery cells are situated on the secondside; and the plurality of electrically-connecting means are on thefirst side.

Generally, the light receiving surfaces of the plurality of solarbattery cells, which surfaces receive sunlight, are on one of both sidesof the solar battery module. In this regard, according to the aboveconfiguration, an electrical connection between a plurality of solarbattery modules is made on the other one of the both sides of each ofthe plurality of solar battery modules, i.e., on a side on whichsurfaces opposite to the light receiving surfaces of the plurality ofsolar battery cells are situated. This makes it possible to connect theplurality of solar battery modules in accordance with the presentinvention without affecting electric power generation by the pluralityof solar battery cells. Particularly, in a case where the plurality ofelectrically-connecting means of the bus sections are connected witheach other via the wire, the wire does not shield the light receivingsurfaces of the plurality of solar battery cells against sunlight.Accordingly, the wire can be freely drawn.

It is preferable that the solar battery module in accordance with thepresent invention be configured such that: the second side having secondholes so as to correspond to positions of the respective first holes,through which second holes the bus sections are each partially exposed.

According to this configuration, part, of each of the bus sections,which is right opposite to a corresponding one of the plurality ofelectrically-connecting means, is exposed. That is, the part of each ofthe bus sections is exposed on both sides of the solar battery module.Accordingly, the wire can be welded to corresponding ones of theplurality of electrically-connecting means of the bus sections byparallel gap welding, which is more definite method than soldering.

Specifically, first, the wire is placed on a corresponding one of theplurality of electrically-connecting means through a corresponding oneof the first holes. Next, parallel gap electrodes are pressed to thecorresponding one of the plurality of electrically-connecting meansthrough a corresponding one of the second holes. Then, an electricalcurrent is applied between the parallel gap electrodes. In this way, itis possible to weld the wire to corresponding ones of the plurality ofelectrically-connecting means.

The solar battery module in accordance with the present invention canfurther include: a flexible resin film provided on the first side whichis the opposite side of the second side on which light receivingsurfaces of the respective plurality of solar battery cells aresituated, the flexible resin film being provided between said at leastone solar battery string and said at least one flexible resin layer.Alternatively, the solar battery module in accordance with the presentinvention can further include: a flexible resin film provided on both ofthe first side and the second side of the solar battery module so as tocover said at least one flexible resin layer.

Generally, a flexible resin film is greater in strength than a flexibleresin layer. According to the above configuration, since the flexibleresin film is included in the solar battery module, the solar batterymodule has high strength. Accordingly, the solar battery module keepsits strength even if a thickness of the entire solar battery module isreduced.

Further, according to the configuration in which the flexible resinfilms are provided on both sides of the solar battery module, outersurfaces of the solar battery module are increased in their strength.Accordingly, a rivet etc. can be easily used for physically connecting aplurality of solar battery modules so as to form a solar battery array.

A solar battery array in accordance with the present invention includes:a plurality of the foregoing solar battery modules, the plurality ofsolar battery modules being electrically connected in series with eachother via corresponding ones of the plurality of electrically-connectingmeans, each of which serves as an end of an electrical connection in acorresponding one of the plurality of solar battery modules.

According to this configuration, it is possible to easily produce alarge-scale solar battery array in accordance with the present inventionby connecting the plurality of solar battery modules. In addition,according to the solar battery array in accordance with the presentinvention, it is possible to improve flexibility of the entire solarbattery array because there are no members such as the bus sectionsbetween adjacent ones of the plurality of solar battery modules.

The solar battery array in accordance with the present invention can beconfigured such that: the plurality of solar battery modules arearranged such that adjacent ones of the plurality of solar batterymodules overlap each other at their neighboring ends; and saidneighboring ends are physically connected with each other by bonding,sewing, or a rivet.

According to this configuration, easy methods such as bonding, sewing,or the rivet can be used for physically connecting the plurality ofsolar battery modules. Therefore, it is possible to produce alarge-scale solar battery array at low cost. Further, since theconnection part between adjacent ones of the plurality of solar batterymodules is uniform in its physical structure, mechanical strength of thesolar battery array as a whole is improved.

The solar battery array in accordance with the present invention canfurther include: a wire connected with corresponding ones of theplurality of electrically-connecting means, the two or more of solarbattery strings being electrically connected in series with each othervia the corresponding ones of the plurality of electrically-connectingmeans and the wire.

The invention is not limited to the description of the embodimentsabove, but may be altered within the scope of the claims. An embodimentbased on a proper combination of technical means disclosed in differentembodiments is encompassed in the technical scope of the invention.

INDUSTRIAL APPLICABILITY

The present invention is suitably applicable to a constituent unit of alarge-scale solar battery sheet. The present invention can be employedin for example a solar battery for space application (i.e., a solarbattery for an artificial satellite) or the like.

Reference Signs List

-   20 Solar battery cell-   30 Solar battery string-   31 Inter connector-   32 Bus section-   32 a Electrically-connecting means-   33 a, 33 b, 33 c, 45 a, 45 b Flexible resin layers-   34, 46 a, 46 b Flexible resin films-   38, 47, 48 Holes-   40 50 Solar battery module-   41, 51 Solar battery array-   42 Adhesive agent-   43, 53 Wires-   52 Rivet

1. A solar battery module for constituting a solar battery array,comprising: at least one solar battery string that is constituted by aplurality of solar battery cells electrically connected in series witheach other; bus sections electrically connected with respective endmostones of the plurality of solar battery cells that constitute said atleast one solar battery string; and at least one flexible resin layerprovided on each of both sides, which are a first side and a secondside, of the solar battery module so as to sandwich said at least onesolar battery string and the bus sections, the first side of the bothsides of the solar battery module having first holes, through which thebus sections are each partially exposed, and the bus sections havingareas which are exposed through the respective first holes, the areasserving as a respective plurality of electrically-connecting means. 2.The solar battery module according to claim 1, wherein: a number of saidat least one solar battery string is two or more; and the two or moresolar battery strings are electrically connected in series with eachother via corresponding ones of the plurality of electrically-connectingmeans.
 3. The solar battery module according to claim 2, furthercomprising: a wire connected with corresponding ones of the plurality ofelectrically-connecting means, the two or more solar battery stringsbeing electrically connected in series with each other via thecorresponding ones of the plurality of electrically-connecting means andthe wire.
 4. The solar battery module according to claim 1, wherein:light receiving surfaces of the respective plurality of solar batterycells are situated on the second side; and the plurality ofelectrically-connecting means are on the first side.
 5. The solarbattery module according to clam 1, wherein: the second side havingsecond holes so as to correspond to positions of the respective firstholes, through which second holes the bus sections are each partiallyexposed.
 6. The solar battery module according to claim 1, furthercomprising: a flexible resin film provided on the first side which isthe opposite side of the second side on which light receiving surfacesof the respective plurality of solar battery cells are situated, whereina number of said at least one flexible resin layer provided on the firstside of the solar battery module is two or more, and the flexible resinfilm is provided between the two or more flexible resin layers.
 7. Thesolar battery module according to claim 1, further comprising: aflexible resin film provided on both of the first side and the secondside of the solar battery module so as to cover said at least oneflexible resin layer.
 8. A solar battery array, comprising: a pluralityof solar battery modules recited in claim 1, the plurality of solarbattery modules being electrically connected in series with each othervia corresponding ones of the plurality of electrically-connectingmeans, each of which serves as an end of an electrical connection in acorresponding one of the plurality of solar battery modules.
 9. Thesolar battery array according to claim 8, wherein: the plurality ofsolar battery modules are arranged such that adjacent ones of theplurality of solar battery modules overlap each other at theirneighboring ends; and said neighboring ends are physically connectedwith each other by bonding, sewing, or a rivet.
 10. The solar batteryarray according to claim 8, further comprising: a wire connected withcorresponding ones of the plurality of electrically-connecting means,the plurality of solar battery modules being electrically connected inseries with each other via the corresponding ones of the plurality ofelectrically-connecting means and the wire.